A geostationary satellite orbits around the earth in a circular orbit of radius 36000 km. Then the time period of a spy satellite orbiting a few hundred kilometre above the earth's surface (R_earth = 6400 km) will approximately be

2 h

v = $\sqrt{gR}$ = 7.9 kms^-1, and

$T = \frac{2 \pi R}{v} = \frac{2 \pi 6400 \times 100}{7900}$ = 84.79 minute

is the time period of satellite revolving very close to earth's surface. So time period of spy satellite must be slightly greater and so C is the appropriate answer.